linux-kernel - Re: [PATCH] um: Remove 3-level page table support on i386

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <75b42537-e895-4c3a-85b5-3c9beab3e149@antgroup.com>
Date: Thu, 19 Sep 2024 15:47:42 +0800
From: "Tiwei Bie" <tiwei.btw@...group.com>
To: Benjamin Berg <benjamin@...solutions.net>,
 Johannes Berg <johannes@...solutions.net>, richard@....at,
 anton.ivanov@...bridgegreys.com
Cc: linux-um@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] um: Remove 3-level page table support on i386

On 2024/9/19 15:22, Benjamin Berg wrote:
> On Thu, 2024-09-19 at 08:54 +0200, Johannes Berg wrote:
>> On Wed, 2024-09-18 at 14:17 +0800, Tiwei Bie wrote:
>>> The highmem support has been removed by commit a98a6d864d3b ("um:
>>> Remove broken highmem support"). The 2-level page table is
>>> sufficient
>>> on UML/i386 now. Remove the 3-level page table support on UML/i386
>>> which is still marked as experimental.
>>>
>>
>> No real objection, but with the 4-level page table work on 64-bit
>> pending as well (which likely conflicts), I wonder if we should just
>> remove 3-level *entirely*?

Fine with me in either way. Keeping only one page table implementation
on UML/x86_64 may require smaller maintenance effort.

> 
> Fine with me. There is only the tiny advantage of saving a few pages of
> memory for each process. I just erred on the side of keeping it in case
> anyone is cares to the option …
> 
> I'll resubmit the patchset without 3-level support then, possibly on
> top of this patch.

Thanks! :)

Regards,
Tiwei

> On the assumption that no one actually cares about
> 3-level page tables on x86_64.
> 
> Benjamin